can't override default admin model form django - django

I need to add extra validation to my DateField in Admin to make sure the date given is in the future. I have no experience in such a thing, so here's what I've done.
1) I've created custom form field and added validation to it:
class PastDateField(forms.DateField):
def clean(self, value):
"""Validates if only date is in the past
"""
if not value:
raise forms.ValidationError('Plase enter the date')
if value > datetime.now():
raise forms.ValidationError('The date should be in the past, not in future')
return value
2) Then I've added custom model form:
class CustomNewsItemAdminForm(forms.ModelForm):
title = forms.CharField(max_length=100)
body = forms.CharField(widget=forms.Textarea)
date = PastDateField()
region = forms.ModelChoiceField(Region.objects)
3) And here's how I've registered admin:
class NewsItemAdmin(admin.ModelAdmin):
form = CustomNewsItemAdminForm
def queryset(self, request):
return NewsItem.objects.all()
admin.site.register(NewsItem, NewsItemAdmin)
The result of this is that my admin form
1) Shows field I haven't specified in custom admin form
2) Lacks JavaScript calendar for the datetime field
It's pretty obvious to me that I'm doing something wrong, but I've found no examples relevant to my needs as I am a noob. What is the better way to add custom validation to datetime field without messing things up?
EDIT: Thanks a lot to Brian Luft and Daniel Roseman for correct answers! To make this post helpful for someone facing the same problem here is the resulting code:
class CustomNewsItemAdminForm(forms.ModelForm):
class Meta:
model = NewsItem
def clean_date(self):
"""Validates if only date is in the past
"""
date = self.cleaned_data["date"]
if date is None:
raise forms.ValidationError('Plase enter the date')
if date > datetime.now().date():
raise forms.ValidationError('The date should be in the past, not in future')
return self.cleaned_data["date"]
class NewsItemAdmin(admin.ModelAdmin):
form = CustomNewsItemAdminForm
def queryset(self, request):
return NewsItem.objects.all()
admin.site.register(NewsItem, NewsItemAdmin)

Firstly, declaring fields explicitly on a ModelForm - whether in or out of the admin - does not mean that the other fields will not be displayed. You need to define the fields or exclude tuples in the form's inner Meta class. If the other fields are all the default, you can simply declare the one you are overriding.
Secondly, if you want your custom field to use the javascript, you'll need to use the right widget, which is django.contrib.admin.widgets.AdminDateWidget. However, there is a much easier way to do this, which is not define a custom field at all, but instead define a clean_date method on the form itself.

Related

Fill a form field with initial values from another model (which is a foreign key)

I have 2 models, Company and Post.
class Post(Meta):
company = models.ForeignKey(Company, related_name='company', on_delete=models.CASCADE)
company_description = models.TextField(max_length=800)
What I need:
1) When a user create a post, the company FK will be set thru code
2) Also at form initialization the field company_description, will be prepopulated from the Company model, field description(not the same name)
3) On save if the user doesn't modify anything to the field, the initial value will be save
1,2,3 only on creation.
I checked Django documentation regarding initialization
but their example, is more simple they just get some data/text, in my case I first need to set FK, than get description from the FK Model, so not just text.
The pk/slug of the company I can get from url or from request thru multiple calls request.user.acc.company
path('<int:pk>/post/add/', CompanyPostCreateView.as_view(), name='create')
and in the view:
company_pk = kwargs.get('pk')
and overwrite the form_valid, but here is the issue, form_valid is called on validation, and I want to show this info before validation on form initialization, and I don't know how.
There isn't anything particularly complicated about this. You can get the FK at the start of the view and use it in the initial dictionary:
company = Company.objects.get(pk=company_pk)
form = PostForm(intial={'company_description': company.description})
Edit With a CreateView, you could just override get_initial:
def get_initial(self):
company = Company.objects.get(pk=self.kwargs['pk'])
return {'company_description': company.description}
I found a solution by overwriting get_form_kwargs
def get_form_kwargs(self):
self.company = Company.objects.get(pk=self.kwargs['pk'])
kwargs = super().get_form_kwargs()
kwargs['initial']['company_description'] = self.company.description
return kwargs
I use self.company to pass later to a different method, not redo the query.

Django admin: make field editable in add but not edit

I've got a model similar to this:
class Product(models.Model):
third_party_id = models.CharField(max_length=64, blank=False, unique=True)
that uses the Django default primary key. I want users to be able to add products by setting the third_party_id on the add page, but I don't want that field editable in the edit page to avoid corrupting the third_party_id. In the Django docs, the same settings appear to be used for add and edit. Is this possible?
Do not set self.readonly_fields to avoid thread issues. Instead override get_readonly_fields method:
def get_readonly_fields(self, request, obj=None):
if obj: # obj is not None, so this is an edit
return ['third_party_id',] # Return a list or tuple of readonly fields' names
else: # This is an addition
return []
The above is helpful (shanyu's answer using get_readonly_fields), however it does not work properly if used in "StackedInline". The result is two copies of whatever field is marked readonly, and it is not editable in the "add" instance. See this bug: https://code.djangoproject.com/ticket/15602
Hope this saves someone some searching!
I am not sure if this is the best way, but you could define your own form for the admin. And custom validate your third_party_id, rejecting if it is already set:
Admin.py
class ProductAdminForm(forms.ModelForm):
class Meta:
model = Product
def clean_third_party_id(self):
cleaned_data = self.cleaned_data
third_party_id = cleaned_data['third_party_id']
id = cleaned_data['id']
obj = Product.objects.get(id=id)
if obj.third_party_id != third_party_id:
raise ValidationError("You cannot edit third_party_id, it must stay as %s" % obj.third_party_id)
return third_party_id
class ProductAdmin(admin.Admin):
form = [ProductAdminForm,]

Django "Enter a list of values" form error when rendering a ManyToManyField as a Textarea

I'm trying to learn Django and I've ran into some confusing points. I'm currently having trouble creating a movie using a form. The idea of the form is to give the user any field he'd like to fill out. Any field that the user fills out will be updated in its respective sql table (empty fields will be ignored). But, the form keeps giving me the error "Enter a list of values" when I submit the form. To address this, I thought stuffing the data from the form into a list and then returning that list would solve this.
The first idea was to override the clean() in my ModelForm. However, because the form fails the is_valid() check in my views, the cleaned_data variable in clean() doesn't contain anything. Next, I tried to override the to_python(). However, to_python() doesn't seem to be called.
If I put __metaclass__ = models.SubfieldBase in the respective model, I receive the runtime error
"TypeError: Error when calling the
metaclass bases
metaclass conflict: the metaclass of a derived class must be a
(non-strict) subclass of the
metaclasses of all its bases"
My approach doesn't seem to work. I'm not sure how to get around the 'Enter a list of values" error! Any advice?
Here is the relevant code (updated):
models.py
""" Idea:
A movie consists of many equipments, actors, and lighting techniques. It also has a rank for the particular movie, as well as a title.
A Theater consists of many movies.
A nation consists of many theaters.
"""
from django.db import models
from django.contrib.auth.models import User
class EquipmentModel(models.Model):
equip = models.CharField(max_length=20)
# user = models.ForeignKey(User)
class ActorModel(models.Model):
actor = models.CharField(max_length=20)
# user = models.ForeignKey(User)
class LightModel(models.Model):
light = models.CharField(max_length=20)
# user = models.ForeignKey(User)
class MovieModel(models.Model):
# __metaclass__ = models.SubfieldBase
rank = models.DecimalField(max_digits=5000, decimal_places=3)
title = models.CharField(max_length=20)
equipments = models.ManyToManyField(EquipmentModel, blank=True, null=True)
actors = models.ManyToManyField(ActorModel, blank=True, null=True)
lights = models.ManyToManyField(LightModel, blank=True, null=True)
class TheaterModel(models.Model):
movies = models.ForeignKey(MovieModel)
class NationModel(models.Model):
theaters = models.ForeignKey(TheaterModel)
=====================================
forms.py
"""
These Modelforms tie in the models from models.py
Users will be able to write to any of the fields in MovieModel when creating a movie.
Users may leave any field blank (empty fields should be ignored, ie: no updates to database).
"""
from django import forms
from models import MovieModel
from django.forms.widgets import Textarea
class MovieModelForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(MovieModelForm, self).__init__(*args, **kwargs)
self.fields["actors"].widget = Textarea()
self.fields["equipments"].widget = Textarea()
self.fields["lights"].widget = Textarea()
def clean_actors(self):
data = self.cleaned_data.get('actors')
print 'cleaning actors'
return [data]
class Meta:
model = MovieModel
=============================================
views.py
""" This will display the form used to create a MovieModel """
from django.shortcuts import render_to_response
from django.template import RequestContext
from forms import MovieModelForm
def add_movie(request):
if request.method == "POST":
form = MovieModelForm(request.POST)
if form.is_valid():
new_moviemodel = form.save()
return HttpResponseRedirect('/data/')
else:
form = MovieModelForm()
return render_to_response('add_movie_form.html', {form:form,}, context_instance=RequestContext(request))
The probable problem is that the list of values provided in the text area can not be normalized into a list of Models.
See the ModelMultipleChoiceField documentation.
The field is expecting a list of valid IDs, but is probably receiving a list of text values, which django has no way of converting to the actual model instances. The to_python will be failing within the form field, not within the form itself. Therefore, the values never even reach the form.
Is there something wrong with using the built in ModelMultipleChoiceField? It will provide the easiest approach, but will require your users to scan a list of available actors (I'm using the actors field as the example here).
Before I show an example of how I'd attempt to do what you want, I must ask; how do you want to handle actors that have been entered that don't yet exist in your database? You can either create them if they exist, or you can fail. You need to make a decision on this.
# only showing the actor example, you can use something like this for other fields too
class MovieModelForm(forms.ModelForm):
actors_list = fields.CharField(required=False, widget=forms.Textarea())
class Meta:
model = MovieModel
exclude = ('actors',)
def clean_actors_list(self):
data = self.cleaned_data
actors_list = data.get('actors_list', None)
if actors_list is not None:
for actor_name in actors_list.split(','):
try:
actor = Actor.objects.get(actor=actor_name)
except Actor.DoesNotExist:
if FAIL_ON_NOT_EXIST: # decide if you want this behaviour or to create it
raise forms.ValidationError('Actor %s does not exist' % actor_name)
else: # create it if it doesnt exist
Actor(actor=actor_name).save()
return actors_list
def save(self, commit=True):
mminstance = super(MovieModelForm, self).save(commit=commit)
actors_list = self.cleaned_data.get('actors_list', None)
if actors_list is not None:
for actor_name in actors_list.split(","):
actor = Actor.objects.get(actor=actor_name)
mminstance.actors.add(actor)
mminstance.save()
return mminstance
The above is all untested code, but something approaching this should work if you really want to use a Textarea for a ModelMultipleChoiceField. If you do go down this route, and you discover errors in my code above, please either edit my answer, or provide a comment so I can. Good luck.
Edit:
The other option is to create a field that understands a comma separated list of values, but behaves in a similar way to ModelMultipleChoiceField. Looking at the source code for ModelMultipleChoiceField, it inhertis from ModelChoiceField, which DOES allow you to define which value on the model is used to normalize.
## removed code because it's no longer relevant. See Last Edit ##
Edit:
Wow, I really should have checked the django trac to see if this was already fixed. It is. See the following ticket for information. Essentially, they've done the same thing I have. They've made ModelMutipleChoiceField respect the to_field_name argument. This is only applicable for django 1.3!
The problem is, the regular ModelMultipleChoiceField will see the comma separated string, and fail because it isn't a List or Tuple. So, our job becomes a little more difficult, because we have to change the string to a list or tuple, before the regular clean method can run.
class ModelCommaSeparatedChoiceField(ModelMultipleChoiceField):
widget = Textarea
def clean(self, value):
if value is not None:
value = [item.strip() for item in value.split(",")] # remove padding
return super(ModelCommaSeparatedChoiceField, self).clean(value)
So, now your form should look like this:
class MovieModelForm(forms.ModelForm):
actors = ModelCommaSeparatedChoiceField(
required=False,
queryset=Actor.objects.filter(),
to_field_name='actor')
equipments = ModelCommaSeparatedChoiceField(
required=False,
queryset=Equipment.objects.filter(),
to_field_name='equip')
lights = ModelCommaSeparatedChoiceField(
required=False,
queryset=Light.objects.filter(),
to_field_name='light')
class Meta:
model = MovieModel
to_python AFAIK is a method for fields, not forms.
clean() occurs after individual field cleaning, so your ModelMultipleChoiceFields clean() methods are raising validation errors and thus cleaned_data does not contain anything.
You haven't provided examples for what kind of data is being input, but the answer lies in form field cleaning.
http://docs.djangoproject.com/en/dev/ref/forms/validation/#cleaning-a-specific-field-attribute
You need to write validation specific to that field that either returns the correct data in the format your field is expecting, or raises a ValidationError so your view can re-render the form with error messages.
update: You're probably missing the ModelForm __init__ -- see if that fixes it.
class MovieModelForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(MovieModelForm, self).__init__(*args, **kwargs)
self.fields["actors"].widget = Textarea()
def clean_actors(self):
data = self.cleaned_data.get('actors')
# validate incoming data. Convert the raw incoming string
# to a list of ids this field is expecting.
# if invalid, raise forms.ValidationError("Error MSG")
return data.split(',') # just an example if data was '1,3,4'

Django Forms: Hidden model field?

I've got a Form. I want to include a hidden field that returns a model. I'll set it's value in the view; I just need it to be posted along to the next page.
What field am I supposed to use in the form class?
A hidden field that returns a model? So a model instance ID?
The forms.HiddenInput widget should do the trick, whether on a FK field or CharField you put a model instance ID in.
class MyForm(forms.Form):
hidden_2 = forms.CharField(widget=forms.HiddenInput())
hidden_css = forms.CharField(widget=forms.MostWidgets(attrs={'style': 'display:none;'}))
I suppose the fastest way to get this working is
class MyForm(forms.Form):
model_instance = forms.ModelChoiceField(queryset=MyModel.objects.all(), widget=forms.HiddenInput())
form = MyForm({'model_instance': '1'})
form.cleaned_data['model_instance']
But I don't like the idea of supplying MyModel.objects.all() if you're going to specify one item anyways.
It seems like to avoid that behavior, you'd have to override the form __init__ with a smaller QuerySet.
I think I prefer the old fashioned way:
class MyForm(forms.Form):
model_instance = forms.CharField(widget=forms.HiddenInput())
def clean_model_instance(self):
data = self.cleaned_data['model_instance']
if not data:
raise forms.ValidationError()
try:
instance = MyModel.objects.get(id=data)
except MyModel.DoesNotExist:
raise forms.ValidationError()
return instance
The approach in Yuji's answer uses a clean_model_instance method on the form which is fine if you're only ever doing this once in your code base. If you do it more often, then you might benefit from implementing a custom model field.
This is the code I have:
from django import forms
class ModelField(forms.Field):
Model = None
def prepare_value(self, value):
"""Inject entities' id value into the form's html data"""
if isinstance(value, self.Model):
return value.id
return value
def to_python(self, value):
"""More or less stolen from ModelChoiceField.to_python"""
if value in self.empty_values:
return None
try:
value = self.Model.objects.get(id=value)
except (ValueError, self.Model.DoesNotExist):
raise forms.ValidationError('%s does not exist'
% self.Model.__class__.__name__.capitalize())
return value
If you use that as a base class and then specialise it with your own models then it becomes a useful based. For example:
# In app/fields.py
from .models import CustomModel
class CustomModelField(ModelField):
Model = CustomModel
Then you can pair that with whatever widget you need at the time:
# in app/forms.py
class MyForm(forms.Form):
hidden_custom_model_field = CustomModelField(widget=forms.HiddenInput())
other_widget_custom_model_field = CustomModelField(widget=MyCustomWidget())

django manytomany validation

Please see the code below. Basically, when the user creates an object of this class, they need to specify the value_type. If value_type==2 (percentage), then percentage_calculated_on (which is a CheckboxSelectMultiple on the form/template side needs to have one or more items checked. The model validation isn't allowing me to validate like I'm trying to -- it basically throws an exception that tells me that the instance needs to have a primary key value before a many-to-many relationship can be used. But I need to first validate the object before saving it. I have tried this validation on the form (modelform) side (using the form's clean method), but the same thing happens there too.
How do I go about achieving this validation?
INHERENT_TYPE_CHOICES = ((1, 'Payable'), (2, 'Deductible'))
VALUE_TYPE_CHOICES = ((1, 'Amount'), (2, 'Percentage'))
class Payable(models.Model):
name = models.CharField()
short_name = models.CharField()
inherent_type = models.PositiveSmallIntegerField(choices=INHERENT_TYPE_CHOICES)
value = models.DecimalField(max_digits=12,decimal_places=2)
value_type = models.PositiveSmallIntegerField(choices=VALUE_TYPE_CHOICES)
percentage_calculated_on = models.ManyToManyField('self', symmetrical=False)
def clean(self):
from django.core.exceptions import ValidationError
if self.value_type == 2 and not self.percentage_calculated_on:
raise ValidationError("If this is a percentage, please specify on what payables/deductibles this percentage should be calculated on.")
I tested out your code in one of my projects' admin app. I was able to perform the validation you required by using a custom ModelForm. See below.
# forms.py
class MyPayableForm(forms.ModelForm):
class Meta:
model = Payable
def clean(self):
super(MyPayableForm, self).clean() # Thanks, #chefsmart
value_type = self.cleaned_data.get('value_type', None)
percentage_calculated_on = self.cleaned_data.get(
'percentage_calculated_on', None)
if value_type == 2 and not percentage_calculated_on:
message = "Please specify on what payables/deductibles ..."
raise forms.ValidationError(message)
return self.cleaned_data
# admin.py
class PayableAdmin(admin.ModelAdmin):
form = MyPayableForm
admin.site.register(Payable, PayableAdmin)
The Admin app uses the SelectMultiple widget (rather than CheckboxSelectMultiple as you do) to represent many to many relationships. I believe this shouldn't matter though.